Hi All, This is V3 of patches. I had posted version v2 version here. https://lore.kernel.org/linux-fsdevel/20200807195526.426056-1-vgoyal@xxxxxxxxxx/ I have taken care of comments from V2. Changes from V2 are. - Rebased patches on top of 5.9-rc1 - Renamed couple of functions to get rid of iomap prefix. (Dave Chinner) - Modified truncate/punch_hole paths to serialize with dax fault path. For now did this only for dax paths. May be non-dax path can benefit from this too. But that is an option for a different day. (Dave Chinner). - Took care of comments by Jan Kara in dax_layout_busy_page_range() implementation patch. - Dropped one of the patches which forced sync release in fuse_file_put() path for DAX files. It was redundant now as virtiofs already sets fs_context->destroy which forces sync release. (Miklos) - Took care of some of the errors flagged by checkpatch.pl. Description from previous post ------------------------------ This patch series adds DAX support to virtiofs filesystem. This allows bypassing guest page cache and allows mapping host page cache directly in guest address space. When a page of file is needed, guest sends a request to map that page (in host page cache) in qemu address space. Inside guest this is a physical memory range controlled by virtiofs device. And guest directly maps this physical address range using DAX and hence gets access to file data on host. This can speed up things considerably in many situations. Also this can result in substantial memory savings as file data does not have to be copied in guest and it is directly accessed from host page cache. Most of the changes are limited to fuse/virtiofs. There are couple of changes needed in generic dax infrastructure and couple of changes in virtio to be able to access shared memory region. Thanks Vivek Sebastien Boeuf (3): virtio: Add get_shm_region method virtio: Implement get_shm_region for PCI transport virtio: Implement get_shm_region for MMIO transport Stefan Hajnoczi (2): virtio_fs, dax: Set up virtio_fs dax_device fuse,dax: add DAX mmap support Vivek Goyal (13): dax: Modify bdev_dax_pgoff() to handle NULL bdev dax: Create a range version of dax_layout_busy_page() virtiofs: Provide a helper function for virtqueue initialization fuse: Get rid of no_mount_options fuse,virtiofs: Add a mount option to enable dax fuse,virtiofs: Keep a list of free dax memory ranges fuse: implement FUSE_INIT map_alignment field fuse: Introduce setupmapping/removemapping commands fuse, dax: Implement dax read/write operations fuse,virtiofs: Define dax address space operations fuse, dax: Serialize truncate/punch_hole and dax fault path fuse,virtiofs: Maintain a list of busy elements fuse,virtiofs: Add logic to free up a memory range drivers/dax/super.c | 3 +- drivers/virtio/virtio_mmio.c | 31 + drivers/virtio/virtio_pci_modern.c | 95 +++ fs/dax.c | 29 +- fs/fuse/dir.c | 32 +- fs/fuse/file.c | 1198 +++++++++++++++++++++++++++- fs/fuse/fuse_i.h | 114 ++- fs/fuse/inode.c | 146 +++- fs/fuse/virtio_fs.c | 279 ++++++- include/linux/dax.h | 6 + include/linux/virtio_config.h | 17 + include/uapi/linux/fuse.h | 34 +- include/uapi/linux/virtio_fs.h | 3 + include/uapi/linux/virtio_mmio.h | 11 + include/uapi/linux/virtio_pci.h | 11 +- 15 files changed, 1933 insertions(+), 76 deletions(-) Cc: Jan Kara <jack@xxxxxxx> Cc: Dave Chinner <david@xxxxxxxxxxxxx> Cc: Christoph Hellwig <hch@xxxxxxxxxxxxx> Cc: Ira Weiny <ira.weiny@xxxxxxxxx> Cc: "Michael S. Tsirkin" <mst@xxxxxxxxxx> Cc: Vishal L Verma <vishal.l.verma@xxxxxxxxx> -- 2.25.4
